Implement position control mechanism



June 8, 1965 0. s. STRADER ETAL 3,187,913

IMPLEMENT POSITION CONTROL MECHANISM Filed April 30, 1963 2 Sheets-Sheet1 June 8, 1965 D. s. STRADER ETAL 3,187,913

IMPLEMENT POSITION CONTROL MECHANISM Filed April 30, 1963 2 Sheets-Sheet2 ----NEUTRAL -BREAKOUT United States Patent 0 3,187,913 IMPLEMENTPOSITION (IUNTROL MECHANISM Don S. Strader, Mount Prospect, and RobertG. Lutt, Wildwood, IlL, assignors to The Frank G. Hough Co.,

a corporation of Illinois Filed Apr. 36, 1963, Ser. No. 276,913 4Claims. (Cl. 2I4-I4il) This invention relates generally to tool orimplement control mechanisms wherein a tool is operatively carried froma vehicle and is movable through a certain range under control of theoperator of the vehicle, and more particularly to a novel arrangementproviding automatic indexing of the tool in some predetermined positionintermediate the range of movement of the tool; In the presentembodiment of the invention the novel automatic indexing arrangement isapplied to a front-end-type tractor loader.

The primary object of the present invention is to provide a novelarrangement for accurately and positively indexing a vehicle-carriedmovable tool in some predetermined postion intermediate the range ofmovement of the tool.

It is a further object to provide a novel arrangement for accurately andpositively indexing the bucket of a frontend-type tractor loader in apredetermined position.

It is a further object to provide novel indexing means for ahydraulically-operated front-end-type tractor loader which will operatein cooperation with thebucket-tilting means thereof to provide automaticindexing of the bucket in a predetermined tilted position.

It is still another object to provide a novel construction inarrangements of the preceding paragraphs so that the automaticindexingfunction may be easily and manually overridden. 1

It is a further object toprovide a novel indexing arrangement for thebucket'of a front-end-type tractor loader which will automaticallyoperate when the bucket is being pivoted from a dump position toward adigging position to stop the bucket in a predetermined digging position.

It is a further object to provide a novel tool-indexing arrangementwhich can easily be applied to and incorporated in the hydraulic circuitmeans of existingtypes of vehicle-carried hydraulically-movable tools,to provide automatic indexing of the tool in a predetermined position.

Other objects and features of the invention will be ap parent upon aperusal of the following specification and drawings, in which:

FIGURE 1 is a side elevational view of a front-end-type tractor loaderconstructed according to the present invention;

FIGURE 2 is an enlarged partial view of the indicator means of FIGURE 1for indicating the pivoted position of the bucket shown in FIGURE 1;

FIGURE 3 is an enlarged end view of the shown in FIGURE 2;

FIGURE 4 is an enlarged partial view of a portion structure of thestructure in FIGURE 2;

FIGURE 5 is an enlarged side elevational view of the valve arrangementof FIGURE 1 with the hydraulic apparatus connected thereto being shownin reduced scale and substantially diagrammatical;

FIGURE 6 is an enlarged side view of a portion of the structure shown inFIGURE 5;

FIGURE 7 is a diagrammatic view of a portion of the hydraulic circuitsof the invention; and

FIGURE 8 is an electric circuit diagram of a portion of the invention. L

The present embodiment is the preferred embodiment, but it is to beunderstood that changes can be made in the present embodiment by oneskilled in the art without departing from the spirit and scope of thepresent invention.

Patented June 8, 1965 Generally, the novel indexing means in the presentembodiment of the invention is applied to a front-endtype tractor loaderand is partially carried on the tractor and partially carried on thebucket-tilting assembly thereof. The bucket-tilting assembly of thetractor loader includes a double-acting hydraulic cylinder, one end ofwhich is pivotally carried on the tractor, and the other end of which isconnected to the bucket by a linkage and leverage arrangement. Thedouble-acting hydraulic cylinder is selectively extended or retracted topivot the bucket relative to the boom. In the present embodiment, anextension of the. hydraulic cylinder causes the bucket to be pivotedrearwardly to what is commonly called'the breakout position. Asubstantially complete retraction of the hydraulic cylinder will causethe bucket to be pivoted to a dump position. The digging position of thebucket is intermediate the breakout and dump positions.

The bucket hydraulic cylinder is selectively extended and retracted bymeans of a manually operated hydraulic control valve carried in theoperators compartment of the tractor. The hydraulic control valvecomprises a valve body having a bucket valve spool slidably carriedtherein for longitudinally reciprocating movement. The control valve mayinclude a spool for controlling the operation of the cylinder-forraising and lowering the boom; however, since the boom hydraulic circuitforms no part of the present invention, any showing or descriptionrelative thereto may be omitted.

The bucket valve spool is manually reciprocated by a hand lever assemblyconnected thereto. Each end of the hydraulic cylinder for tilting thebucket is connected by suitable conduits into the valve bore for thebucket spool. A source of hydraulic fluid pressure and a reservoir arealso connected to the control valve. It is contemplated in the presentinvention that the control valve be of the type commonly known as anopen-center valve. In such a valve, the bucket valve spool is normallyspring-biased to a center neutral position. In the center neutralposition, both ends of the buckethydraulic cylinder are blocked and thesource of hydraulic fluidpressure is connected to the reservoir conduit.Moving the hand lever to move the bucket spool in one direction from thecenter neutral position will cause the source of hydraulic fluidpressure to be connected to one end of the hydraulic cylinder while theother end of the hydraulic cylinder is connected to the reservoir.Manual movement of the hand lever to move the bucket spool in theopposite direction from the center neutral position will cause areversal of the connections of the source of hydraulic fluid pressureand the reservoir to the hydraulic cylinder. Thus it may be seen thatwhen the operator of the tractor loader moves the bucket spool handlever in one direction, the bucket ispivoted in one direction, and whenthe operator moves that hand lever in the opposite direction, the bucketis pivoted in the opposite direction. When the hand lever is released,the bucket is stopped in whatever pivoted position it had attained priorto release of the hand lever.

In the present embodiment of the invention, the extending end of thebucket spool, which is connected to the hand lever by means of a linkand lever assembly, is provided with a detent plate on a pair of linksconnecting the extending end of'the bucket spool to a lever on the handlever assembly A spring-biased and air-retracted pawl assembly iscarried in cooperation with the detent plate so that when the handleveris pivoted to move the bucket spool to the operated position thereof forpivoting of the bucket toward the breakout position, the tip of thespring-biased and air-retracted pawl assembly will engage a notch in thedetent plate to hold the bucket spool and the hand lever assembly inthat operated position, thereby enabling the operator to release thehand lever. When the spring-biased pawl is holding the bucket spool, the

sass/p13 holding force exerted thereby is suflicient to overcome anyforce of the bucket spool biasing means tending to return the bucketspool to the center neutral position. Theanotchdn'the detent plate which'is' engaged by the spring biased pawl is so shaped that when thetractor operator manually'atternpts to return the bucket spool to thecenter neutral position, the spring-biased pawl will slip fr'om thenotch in the 'detent plate to "permit-the bucket spool to be manuallyreturned to the center neutral positior 1.; Thus the holding function ofthesp'ring-biase'd pawl and the detent plate is relatively "easilymanually overridden. g

, When the hand lever is pivoted to move: the bucket spool between thecenter neutral position and the operated position thereof for pivotingof the buckettowa'rd the dump position, the'tip of the spring biasedpawl will slide over the surface of the detent plate and any forceexerted. by the spring-biased pawl on the detent plate will bein'suflicient to maintain the hand lever'asse'mbly and the bucket spoolin the dilmp position so that if the hand lever assembly is released bythe tractor operator when the bucket spool is in the du-mpposition, thespringbiasing means for the bucket spool willreturn the bucket spool andthe hand lever assembly to the center neutral position. I The threepositions of the bucket spool are indicated in FIGURE 6 by the legendsBREAKOUT, NEUTRAL, and DUMP. The spring-biased and air-retracted pawlassembly in the present embodiment comprises a small air cylinder withthe pawl being defined by the tip, of the piston rod of the aircylinder. A compressed coiled spring is carried between the head end ofthe air cylinder and piston head to bias the piston rod to an extendedposition. ,An air conduit is connected to the rod end of the aircylinder to pr'ovidefor retraction of the piston rod against the bias ofthe coiled spring responsive to the application of air under pressure tothe conduit.

The above described arrangement is combined with certain indicator meansfor controlling the application of air under pressure to the"spring-biased and air-retracted pawl assembly to release the bucketspool and hand lever assembly when the bu termined pivoted position.Thespecific indicator means used in the present embodiment is byway ofexample only as many other types of indicator means may be used tocontrol the application'of air under pressure to the springbiased'and'air-retracted pawl assembly. In the present embodiment the indicatormeans comprises a pointer movable over a scale, and the pointer is movedin response to extensions and retractions of the bucket tiltingcylinder. cylinder are used in the 'pressent embodimentrbecausethevarious pivoted positions of the bucket are a direct function of thevarious extended and retractedpositions' of the bucket'cylinder.When'the pointer of the indicator means indicates acertainipi'edetermined pivoted position of the bucket on the scale,suchas the digging position shown in FIGURE 1, an electric switch isoperated by thefpointer'atthat position. When the electric switch isoperated by the pointer, a circuit is completed for operation of asolenoid-operated air valve. When the solenoidoper'ated' air valveisoperated, a source of air under pressfieisconnectedito"the spring biasedand air retracted pawl assemblytocause' itsretractioii. Thus it may beseen that'when, in response to initial movement of hand lever'a's's'eniblytothe breakout position, the bucket reaches the diggingposition in m oving from the dump position toward the breakout position,the spring-biased and airretracted pawl i s retracted from the notch ithe detent plate tofpermit the bucket spool to be returnedto the centerneutr al positionunder the influence of the springbiasing of the bucketspool. When the bucket spool returns to the center neutral position, thebucket cylinder is stopped, and the bucket is indexed in the diggingposinon.

'cket has attained a certain prede The extensions and retractions of thebucket The present invention also contemplates that the spring biasedand air-retracted assembly may be retracted by a fluid other than air.For example, a suitable hydraulic fluid arrangementmay be used. c r aThe present invention, finds particular application to vehicle-carriedmovable tools .or implements wherein by virtue of the distanceorposition of 11151001 relativeto the operator of the vehicle theaccurate-positioning of the tool or implement insome positionintermediate the range of movement of the tool is diificult. Thiscondition commonly occurs in the art-offront-end type tractor loaderswherein due to the size of the tractor loader and the location-of theoperator relative to the cutting edge of the bucket,- it isvery.;-difficultto adjust the pivoted position of. thebucket to achievean accurate ground-level digging position. ;When applied-to afrontendtype ,tractor loader, the present invention; substantially increases theefiiciency. of :the tractor loader by freeing the operator of thetractor loader from the necessity of repeatedly attemptingtoposition-t-he bucket in the digging position. In the I customaryfront-endtype trace tor loader, the work cycle of digging a load,;tilting the bucket to the breakout position, raising,theboom to aposition for convenient carryingof the bu,cket, carrying the loadedbucket to-a positionv fondumping generally further raising the boom fordumping of the loaded bucket onto a pile. or into a truck, pivoting thebucket to .the dump position todeposit the load, lowering the-boom andpivoting the bucket from thev dump position tothe dig ging position, isconstantly repeated. The present invention results in a substantialreductiondnwork cycle time by permitting the operator of theiloader tomove the hand lever of the bucket'controbyalye to the position forpivoting of the bucketfronpthe dumppositionto- Ward the diggingposition, and While the bucket is1pivoting toward the diggingv positionwithout any further attention from theroperator,the operatormayconcentrateon lowering the boom and returningthe, tractor to thedigging area.- The -procedure,enablestheoperator to move more rapidlyand effectively to control the tractor loader to substantially shortenthe work cycle time. Further, because the operators position rearwardlyand above the bucket is removed asubstantial distance-from the cuttingedge of the bucket, it is,oftentimes diflicult It will be apparent fromthe hereinafter. following de tailed description of the ,pres entembodimentof the invention. that the invention may be,,used toindex thebucket in pivoted positions other thanthe digging posi tion, or thatsome tool'or-implementotherfithana digging bucket may be indexed in;son1e particular position, or that the invention might also be appliedto, the hydraulic cylinder assembly for raising and loweringthe boom toprovide for automatic indexing of the boom in some predeterminedposition. i g

In detail, one type of tractorloader is shown in side elevation inFIGURE 1 with the boom in alowered position and with the bucket in thedigging position. The tractor comprises av frame. 10 supported, ,on'.rearward wheels 11 and forward wheels '12. An, opjeratorfs compartment13 is carried on the frame 10 forwardly of an engine compartmentld' 1 YThe loader comprisesya boom: assembly AS iWhich is pivotally connectedat the. rearward end thereof to the tractor by a pin means 16. The'otherend of the boom assembly 15 extends forwardly of the tractor. Theforward end of the boom assembly 15 is raised and lowered by hydrauliccylinder means, such as hydraulic cylinder 17. The head end of thehydraulic cylinder 17 is pivotally connected to a bracket 18 by a pin19. The bracket 18 is secured to the frame 14) of the tractor to dependtherefrom. The rod end of the hydraulic cylinder 17 is pivotallyconnected to the boom assembly intermediate the ends thereof by a pin20. g y i A digging bucket 21 having a cutting edge 22 carried on theforward marginal edge of the bottom wall thereof is pivotally carried onthe forward end of the boom assembly 15. Flanges, such as flange 23,secured to the rearward side of the bucket 21 are provided for thepivotal connection of the bucket 21 to the boom assembly 15. A pinassembly 24 is journaled through the flange 23 and the forward end ofthe boom assembly 15.

The pivotal position of the bucket 21 relative to the boom assembly 15is determined by bucket-tilting means comprising a hydraulic cylinder25, a lever assembly 26 and a link assembly 27. The head end of thehydraulic cylinder 25 is pivotally connected to :a bracket 23 by a pin30. The bracket 28 is carried on the forward end of the tractorsubstantially at the transverse center thereof. The rod end of thehydraulic cylinder is pivotally connected to one end of the leverassembly 26 by a pin assembly 31. The lever assembly 26 is pivotallycarried intermediate the ends thereof on the boom assembly 15intermediate the ends thereof bya pin assembly 32. The other end of thelever assembly 26 is pivotalpin assembly 33. The other end of the linkassembly 27 is pivotally connected to the flanges 23 on the rear wall ofthe bucket by a pin assembly 34. The various described members of thebucket-tilting means are relatively sized and positioned so that whenthe hydraulic cylinder 25 is partially extended and the boom issubstantially lowered as shown in FIGURE 1, the lever assembly 26 ispositioned in a substantially vertical direction and the bucket 21 ispositioned in the ground level digging position. When the hydrauliccylinder 25 is substantially completely extended, the bucket 21 ispivoted rearwardly about theaxis of the pin assembly 24 to the breakoutposition. When the hydraulic cylinder 25 is substantially retracted, thebucket is pivoted forwardly to the dump position.

A main control valve 36, shown in FIGURES 1 and 5, is provided forselective operation of the hydraulic cylinder 25 by the operator of thetractor loader. Although not shown in the drawings, the main controlvalve 36 may also include valve means for selective operation of thehydraulic cylinder 17 by the operator of the tractor loadern The maincontrol valve 36 is carried in the operators compartment 13 at aconvenient location therein for manual operation. FIGURE 5 shows theconnection of the hydraulic cylinder 25 to the main control valve 36.The main control valve 36 comprises a bucket spool 37 carried in a valveborefor longitudinal reciprocating movement therein. The upper end ofthe bucket spool 37 extends outwardly of the body of the valve 35. Theother or lower end of the bucket spool 37 is provided'with a biasingassembly 38 forbiasing the bucket spool 37 to a center neutral position.The'biasing assembly 38 permits the bucket spool 37 to be moved ineither direction from the centerneutral position to different operatedpositions; The different operated positions in each direction from thecenter neutral position are indicated in FIGURE 6 by the legendsBREAKOUT and DUMP on either side of the legend NEUTRAL for the centerneutral position. The biasing assembly 38 is shown in cross section inFIGURE 5, and may be seen to comprise a pair of washers 40 disposedabout a reduced section of the bucket spool 37 with a compressed coilspring 41 carried between the'washers 40. In FIG- URES 5 and 6, thebucket spool 37 is shown in the center neutral position, and it may beseen that if the extending end of the bucket spool 37 is moved eitherdown- 1y connected to one end of the link assembly 27 by a i wardly orupwardly, one of the washers 45 will be moved off of its seat in thehousing of the assembly 38 by the abutting portion of the bucket spool37 to further compress the coiled spring 41. If the upper extending endof the bucket spool 37 is moved downwardly, the upper washer will beunseated, and if the upper extending end of the bucket spool 37 is movedupwardly from the center neutral position, the lower washer 49 will beunseated. It may be seen that if the bucket spool 37 is free to movefrom one of the operated positions, the compressed coiled spring 41will, in reacting against the seated washer 40, apply a force to theother washer 40 and in turn to the bucketspool 37 to return the bucketspool 37 to the center neutral position. The specific describedarrangement 33 for biasing the bucket spool 37 to the center neutralposition is by way of example only, and it should be understood thatmany other types of selfcentering arrangements may be used for thebucket spool 37.

A hydraulic fluid pump 42, capable of supplying sufficient hydraulicfluid under pressure for operation of the hydraulic cylinder 25, isprovided, and the pressure side of the pump 42 is connected to one endof the conduit 43. The otherend of the conduit 43 is connected into thevalve 35. The suction side of the pump 42 is connected by a conduit 44to a hydraulic fluid reservoir 45. The hydraulic fluid reservoir 45 isalso connected to the valve 36 by a return hydraulic fluid conduit 46.The bucket spool 37 and the valve bore carrying the bucket spool 37 areprovided with suitable lands and grooves (not shown), cooperating withthe connections of the hydraulic cylinder 25 and the connections of thecon duits 43 and 45 to the valve 36 so that when the bucket spool 37 ispositioned in the center neutral position, the conduits to the hydrauliccylinder 25 are blocked, and

. conduit 43 is connected through the valve bore to conduit 46. Thelands and grooves are further so formed thatwhen the upper extending endof the bucket spool 37 is moved upwardly from its center neutralposition, conduits 43 and 46 are connected to the conduits of thehydraulic cylinder 25 so that hydraulic fluid under pressure isdelivered to the rod end of the hydraulic cylinder 25 while the head endthereof is connected to the reservoir 4-5 to cause a retraction of thehydraulic cylinder 25and a consequent pivoting of the bucket 21 towardthe dump position. The described lands and grooves are further formed sothat when the upper extending end of the bucket spool 37 is moveddownwardly from the center neutral position, hydraulic fluid underpressure is connected to the head end of the hydraulic cylinder 25 whilethe rod end thereof is connected to the reservoir 45 to cause anextension of the hydraulic cylinder 35 and a consequent pivoting of thebucket 21 toward the breakout position.

'The bucket spool 37 is manually movable against the bias of the coiledspring 41 by appropriate movement of a hand lever 48. The lower end ofthe hand lever 48 is secured to a sleeve 50 to extend radially outwardlytherefrom. A lever arm 51 is also secured to the sleeve 50 to extendradially outwardly therefrom. The sleeve 50 is journaled on ahorizontally extending pin 52. One end of the pin 52 is secured to theupper end of a bracket 53. The lower end of the bracket 53 is secured tothe body of the valve 36 to upstand therefrom. The outer end of thelever arm 51 is pivotally connected between and to one end of a pair oflinks 54 by a pin 55. The pair of links 54 depends from the lever arm 51and the lower end of the pair of links 54 is pivotally connected to theupwardly extending end of the bucket spool 37' by a pin 56. The handlever 48 is arranged on the opposite. side of the sleeve 50 from thelever arm 51 so that when the hand lever 48 is moved downwardly from thecenter neutral position, the bucket spool 37 is moved upwardlytherefrom, and when the hand lever 48 is raised from the center neutralposition, the bucket spool 37 downwardly tothe' other operated position.

Themea'ns which cooperates with 'the'valve 36 and the various membersconnected thereto to provide for automatic indexing of the bucket 21comprises 'a'detent plate angt'a spring-biasedland air retracted pawlassembly 60. The detent plate 58 is seeilred toon'el'ohgituflinat edgeof the pair of depending links '54 sothat the detefit plate58 mhvesin'agenerally vertical direction as the hand lever 48'is pivoted t'o'movethe bucket spool '37 upis moved wardly" and downwardly from the centerneutral position. Theldet'en't plate 58 is provided with a notch 58d. A

. The spring-biased and 'air retracted pawl assembly 6tcompr'ises'a"moutiting'plate 61,":1 fitting'tiz', a small air cylinder63;a'n' assembly of a piston head and a piston rod 65, a compressedcoiled s rings], and aunt 6 8 for securing the entire assembly togetherjThe rod end of the air cylinder 63 abuts one side of the fitting 62, andwith'the fitting 62"is' secured to one side of the plate s1 by'the nut68 threaded'on the fitting 62 on the other side of the plate 61. Theassembly of the piston head 64 and the piston rod 65 is carried in theair cylinder efiwith the piston rod 65 extending through the fitting at,the plate 61 and the nut 68. The head end of the air cylinder 63 isopen'to atmosphere. The compressed coiled spring 67 is carried inthefair eiyliiider 63 between the head end thereof ans'tne iston head 64 tourge the piston fed as outwardly of the air cylinder 63. An ai'rconduitis'connectedto the fitting'62 and a passageway isprovided through thefitting 62 so that any air under pressure de livered to conduit 74 isdirected into therod end of the air cylinder 63 to 'cause a retractionof thepist'on rod 65 against the bias of the coiled spring 67. Theextending end of the piston rod 65 is spherically shaped to defineapa'wlsurface which'ca'n cooperate with the notch 58a of the detentplate 58 to hold the" pair of links against movement. It is obvious thatwhen the pair of links 54 is held against movement, the hand lever 48and the bucket spool 37 are also held against movement. The mountingplate 61 of the spring-biased and air-retracted pawl assembly 60 issecured to the body of the valve 36 so that'the pawl surfaceor" thepistonlrod o'will slide'on the surface of the detent plate 58 when thehand lever es is moved to move the bucket spool 37 upwardly anddownwardlyt The spring-biased" and i air-retracted pawl" assemnl'y 60 isfurther positioned relative to the detentplate 53 so that when the handlever 48 is operated to move the bucket spool 37 downwardly to operatedposition thereof for pivoting of the bucket 21 rearwardly toward thebreak;- 'out position, the pawl surface of the piston rod 55 will engagethe notch 58a of the detent plate 58. The pawl. surface of the pistonred 65 is so'shaped relative to the notch 58a of the detentiplate 58that thehand lever 48 may relatively easily be manually -rnoveddownwardly to move the bucket spool 37 upwardly with the pawl surface ofthe piston rod 65 moving; out of the notchfisa This construe-honprovides an arrangement for relatively easily. m lhually overriding'theautomatic indexing function of e -b a ed and a rt actedip w lasseiiibyMiam t d P a e 5 V .Althqush he d bed. autom ti indexing function mayberelatively easily manually oven. ridden, the holding arrangemeiit of thespring-biased and air-retracted pawras mbw 60 is such that when pawlsurface of the pistonirod 65engag e s' the notch ssaer the detent plate58 the biasing force of thebucket spool biasing arrangement38*canno:nioveihe'bucket spool 37 upwardly to pull the notch 58a away from thepawl surface of thepiston rod 65. From the foregoing, it may beseen'that the hand lever-S is movable to move the bucket spool 37between the center neutral positiorLand the breakout position with pawlsurface of the piston rod .65 merely sliding over the surface of detentplate 58. If

the hand lever 48 is released with the valve spool 37. in the.

operated position for pivoting of the u k 21 toward the dump position,the biasing force of the b k Spool area-ere pissing arrangement" 38; illretain the were: span a? to the mater neutral position thereby; stoppingI pivoting of thebucket Z1 toward the dump position to etiectivelyosiuen'me bucket121 in the tiltedfor pivoted position substantiallyattained when the hand [was re leased. Further, if the hand lever" :48is movedfto move the bucket spool Bitfomfthe cen er neutral position tothe osition for PiYoting the bucket '21 towardt he been out position,the p awl'surface of the piston rod 65 will engage the notch58izfto'hold the bucket spears? in that operated position, therebyenabling t e p rsmr' to release hand lever 48 without aco'nseqentjreturn of the bucket spool37 to the center neutralposition. l

i To release the pawl surface of the piste". JrodldS from the notch58a'of the :detent plate 58 and'lthe reby permit the biasing arrangement38to return "to thebueket spool 37 to the center neutral position, 'aisolenoid operated air valve 72 is provided. The solenoidoperatedaiivalve '72 is diagrammatically shown in FIGURE 7,' and 'asseen therein, the conduit '70 from thespring-biasedand airretracted pawlassembly/ 60 is connected to the'sole'iioidoperatedair.valve'72. An airpressure conduit 73 and an air exhaust conduit 74 are also connected tothe" valve 72. The valve "72" is so constructed that, when thesolenoidthereof is energized, the valve isopera't'd to connect air pressureconduit 73to conduit 70, "and whenthe solenoid thereof is de ene'rgized, the air exhaust conduitf ll is corinected to conduit 7%). A sourceof air'u'nderfpressure 'for conduit 73 is" generally found in existingtractor loaders wherein compressed air is commonly used for operatioi'ivof the wheel brakes of the tractorl' A H The solenoid of thesolenoid-operated'air valve 72 is momentarily operated in the presentembodiment .by an electric switch 75 which is showniniFIG URES' 2, 3,and 8. One sideof the electric switch- 75 connected to. a source ofpower 76, which may be" the storagebattery" of the tractor; The otherside of the oweqsouree 7s is grounded, as isone side of the solenoid ofthe solenoidoperated'air valve '72; ,The other side of'the solenoid isconnected to the other side of electric switch 75;

Asshown in FIGURES l through 4,. thelswiteh 75'is carried in cooperationwith a bucket position indicator mechanism indicated generally at 77 Thespeciiic bucket position indicator mechanism '77 shown in the drawingsis by way of example onlyand many, other types of indicator systemsmaybe usedto operate switch 75. The bucket position indicator mechanism77 comprises an arrangement which operates responsive to extensions andretractions of the bucket-tilting cylinderl2 5 to in dicate on a scalethe various positions to which the bucket 21 is pivoted. This may beaccomplished because the operatedlength of the bucket-tilting cylinder25 is a direct function of the tilted position of the bucket 21.

The indicator mechanism 77 basically comprises three assemblies; aquadrant 78 and tube 89 assembly, an indicator arm 81 and rod 82assembly, and a tube 33 assembly. v i Q N v x The assembly of thequadrant 78 andtube comprises;

the construction of the quadrant 78 as agenerally semi circular platehaving a scaieon the side thereof toward. theoperators compartment 13.Ihe tubularmernberfiti is securedto the lower marginal edgeof thequadrant 78 at the center thereof with the tube 8t extendingperpendicular to the plane of the quadrant 78. A flange 85. is securedto the tube 80 to extend radially therefrom at the end thereof 'whichjissecured tothe quadrant 78. Theouter end of the flange 85 ijs piv otallycarried on the axis of pin; 30 which pivotally conne'cts the head end ofthe bucket cylinder 25 to the bracket 28 on the tractor, Thisarrangement permits the tube 80 to extend parallel to the longitudinalaxis of the bucket cylinder 25 and toward the rod endthereof.

The assembly of the indicator armjdll and rod prises a circular plate 86to which the indicator arm 81 is secured to extend radially therefrom.The circular plate 86 is secured to one end of a bushing and sleevearrangement 87. The bushing and sleeve arrangement 87 is rotativelycarried in the end of the tube 80 which is secured to the quadrant '78so that the indicator arm 81 will sweep over the scale on the quadrant78 when the bushing and sleeve arrangement 87 is rotated. The bushingand sleeve arrangement 87 is held against any lengthwise movementrelative to the tube 80. The rod 82 is carried in the tube 88 and oneend of the rod 82 is secured in the inner end of the sleeve portion ofthe bushing and sleeve arrangement 87. The rod 82 is twisted about itslongitudinal axis as may be seen in FIGURES 2 and 4. From the foregoingit may be seen that if the rod 82 is rotated about its longitudinalaxis, the indicator arm 81 will sweep over the scale on the quadrant 78to indicate the rotated position of the rod 82.

The assembly of the tube 83 comprises a circular plate 88 which issecured over one end of the tube 83. The plate 88 is provided with aslot therethrough having a length and width substantially equal to thewidth and thickness of the rod 82. The rod 82 extends through the slotin the plate 88 and into tube 83. The end of the tube 83 opposite of theend having the plate 88 is provided with a flange 90. The flange 90extends perpendicularly from the longitudinal axis of the tube 83 and atits outer end is pivotally carried on the axis of the pin 31 whichpivotally connects the rod end of the bucket cylinder 25 to the upperend of the lever assembly 26. This arrangement permits the tube 83 toextend parallel to the longitudinal axis of the bucket cylinder 25 andinto the tube 80 in a telescoping arrangement therewith. From theforegoing, it may be seen that as the bucket cylinder 25 is extended andretracted, the tubes 80 and 83 are similarly extended and retracted, andas the tubes 80 and 83 slide longitudinally of each other, the slot inthe plate 88 of the tube 83 will cause rod 82 to be twisted about itslongitudinal axis to in turn cause the indicator arm 81 to sweep acrossthe face of the scale of the quadrant 78.

The various assemblies of the indicator mechanism 77 are so sized andpositioned that when the bucket cylinder 25 is extended to the positionshown in FIGURE 1 with the bucket 21 in the digging position, theindicator arm 81 is disposed substantially vertically on the scale ofthe quadrant 78 to indicate that digging position of the bucket 21 tothe operator of the tractor loader seated in the operators compartment13. When the bucket cylinder 25 is substantially'completely extended topivot the bucket 21 to the breakout position, the indicator arm 81 willindicate that bucket position on one end of the scale of the quadrant78, and when the bucket cylinder 25 is substantially completelyretracted, the indicator arm 81 will be moved to the other end of thescale to indicate the dumping position of the bucket.

The previously described electric switch 75 for operating valve 72 iscarried on quadrant 78 with the operating mechanism of switch 75positioned so that arm 81 engages switch 75 to close its contacts whenarm 81 indicates the digging position of bucket 21 on the scale ofquadrant 78. Because of the slight time delay in the operation of thevarious components of the present embodiment of the invention, switch 75may be positioned on quadrant 78 to be engaged slightly before the exactindication of the digging position by arm 81 as it moves from the dumpposition.

Assuming bucket 21 to be at rest in its dump position,

spool 37 will be in its neutral position so as to direct fluid toreservoir 45 rather than bucket cylinder 25. In order to move bucket 21away from its dump position, spool 21 is manually moved downwardly asshown in FIGURE 6. Detent plate 58 is carried downwardly with spool 37until notch 58a is engaged by rod 65, at which time spool 37 directsfluid to bucket cylinder 25 so as to pivot bucket 21 from its dumpposition toward its breakout position.

Arm 81 indicates the movement of bucket 21. Upon engagement with switch75 solenoid-operated air valve 72 is actuated so as to supply air to therod end of cylinder 63, thus retracting rod 65 from engagement withnotch 58a.

The biasing assembly 38 of spool 37 will then move spool 37 upwardly tothe center neutral position, and extension of the bucket cylinder 25will be stopped with bucket 21 accurately indexed in the diggingposition and with arm 81 indicating that position on the scale ofquadrant 78. By. the time bucket cylinder 25 has stopped with bucket 21indexed in the digging position, arm 81 will have passed over theoperating mechanism of switch 75, and switch 75 will have restored toopen its contacts thereby de-energizing the solenoid of air valve 72.Upon de-energization, the rod end of air cylinder 63 will be connectedto exhaust, and spring 67 will again urge piston rod 65 outwardly withthe pawl surface of piston rod 65 sliding over the surface of detentplate 58.

Having described the invention what is considered new and desired to beprotected by Letters Patent is:

1. For use with a tractor having an implement movably carried therebyand a hydraulic system including a cylinder connected with saidimplement for moving same, valve means in said system connected withsaidcylinder and movable between a neutral position and first and secondoperating positions in which hydraulic fluid is directed to and fromsaid cylinder for moving said implement respectively in first and seconddirections, spring means associated with said valve means for biasingsame toward said neutral position, manually operable means connectedwith said valve means for moving same between said positions, saidmanually operable means including a detent notch movable in accordancewith movement of said valve means, indexing means associated with saidvalve means and including pawl means engageable with said detent notchupon movement of said valve means to said first operating position forholding said valve means in said first operating position, said indexingmeans further including pneumatic means for disengaging said pawl meansfrom said detent notch, and actuating means associated with saidpneumatic means and responsive to movement of said implement in saidfirst direction for actuating said pneumatic means when said implementreaches a predetermined point in the course of its movement in saidfirst direction.

2. The invention according to claim 1, said pneumatic means beingelectrically actuatable, and said actuating means including an implementposition indicator dial, an implement position indicator arm connectedwith said cylinder for movement in response to movement of saidimplement, and electrical means engageable by said arm in the course ofits movement for actuating said pneumatic means.

3. The invention according to claim 2, said electrical means including aswitch engageable by said arm, said switch and said arm being soconstructed and arranged as to be disengaged upon movement of said valvemeans to said neutral position in response to actuation of saidpneumatic means.

4. The invention according to claim 2, said indexing means furtherincluding spring means biasing said pawl means toward engagement withsaid detent notch, said spring means being of such strength that saidmanually operable means is capable of independently moving said valvemeans from said first operating position.

References Cited by the Examiner UNITED STATES PATENTS 1,970,998 8/34Ferris 9l389 X 2,782,946 2/57 Hough 214- 2,853,200 9/58 Beyerstedt214l40 3,045,845 7/62 Hackett et al. 214--l40 HUGO O. SCHULZ, PrimaryExaminer.

1. FOR USE WITH A TRACTOR HAVING AN IMPLEMENT MOVABLY CARRIED THEREBYAND A HYDRAULIC SYSTEM INCLUDING A CYLINDER CONNECTED WITH SAIDIMPLEMENT FOR MOVING SAME, VALVE MEANS IN SAID SYSTEM CONNECTED WITHSAID CYLINDER AND MOVABLE BETWEEN A NEUTRAL POSITION AND FIRST ANDSECOND OPERATING POSITIONS IN WHICH HYDRAULIC FLUID IS DIRECTED TO ANDFROM SAID CYLINDER FOR MOVING SAID IMPLEMENT RESPECTIVELY IN FIRST ANDSECOND DIRECTIONS, SPRING MEANS ASSOCIATED WITH SAID VALVE MEANS FORBIASING SAME TOWARD SAID NEUTRAL POSITION, MANUALLY OPERABLE MEANSCONNECTED WITH SAID VALVE MEANS FOR MOVING SAME BETWEEN SAID POSITIONS,SAID MANUALLY OPERABLE MEANS INCLUDING A DETENT NOTCH MOVABLE INACCORDANCE WITH MOVEMENT OF SAID VALVE MEANS, INDEXING MEANS ASSOCIATEDWITH SAID VALVE MEANS AND INCLUDING PAWL MEANS ENGAGEABLE WITH SAIDDETENT NOTCH UPON MOVEMENT OF SAID VALVE MEANS TO SAID FIRST OPERATINGPOSITION FOR HOLDING SAID VALVE MEANS IN SAID FIRST OPERATING POSITION,SAID INDEXING MEANS FURTHER INCLUDING PNEUMATIC MEANS FOR DISENGAGINGSAID PAWL MEANS FOR SAID DETENT NOTCH, AND ACTUATING MEANS ASSOCIATEDWITH SAID PNEUMATIC MEANS AND RESPONSIVE TO MOVEMENT OF SAID IMPLEMENTIN SAID FIRST DIRECTION FOR ACTUATING SAID PNEUMATIC MEANS WHEN SAIDIMPLEMENT REACHES A PREDETERMINED POINT IN THE COURSE OF ITS MOVEMENT INSAID FIRST DIRECTION.